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 * Licensed to the Apache Software Foundation (ASF) under one   *
 * or more contributor license agreements.  See the NOTICE file *
 * distributed with this work for additional information        *
 * regarding copyright ownership.  The ASF licenses this file   *
 * to you under the Apache License, Version 2.0 (the            *
 * "License"); you may not use this file except in compliance   *
 * with the License.  You may obtain a copy of the License at   *
 *                                                              *
 *   http://www.apache.org/licenses/LICENSE-2.0                 *
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 * Unless required by applicable law or agreed to in writing,   *
 * software distributed under the License is distributed on an  *
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY       *
 * KIND, either express or implied.  See the License for the    *
 * specific language governing permissions and limitations      *
 * under the License.                                           *
 ****************************************************************/

package org.apache.james.server.core.configuration;

import java.io.File;
import java.util.Objects;
import java.util.Optional;

import org.apache.james.filesystem.api.FileSystem;
import org.apache.james.filesystem.api.JamesDirectoriesProvider;
import org.apache.james.server.core.JamesServerResourceLoader;
import org.apache.james.server.core.MissingArgumentException;

import com.google.common.base.MoreObjects;

public interface Configuration {

    String WORKING_DIRECTORY = "working.directory";

    class ConfigurationPath {
        private final String value;

        public ConfigurationPath(String value) {
            this.value = value;
        }

        public String asString() {
            return value;
        }

        @Override
        public final boolean equals(Object o) {
            if (o instanceof ConfigurationPath) {
                ConfigurationPath that = (ConfigurationPath) o;

                return Objects.equals(this.value, that.value);
            }
            return false;
        }

        @Override
        public final int hashCode() {
            return Objects.hash(value);
        }

        @Override
        public String toString() {
            return MoreObjects.toStringHelper(this)
                .add("value", value)
                .toString();
        }
    }

    class Basic implements Configuration {
        public static class Builder {
            private Optional<String> rootDirectory;
            private Optional<ConfigurationPath> configurationPath;

            private Builder() {
                rootDirectory = Optional.empty();
                configurationPath = Optional.empty();
            }

            public Builder workingDirectory(String path) {
                rootDirectory = Optional.of(path);
                return this;
            }

            public Builder workingDirectory(File file) {
                rootDirectory = Optional.of(file.getAbsolutePath());
                return this;
            }

            public Builder useWorkingDirectoryEnvProperty() {
                rootDirectory = Optional.ofNullable(System.getProperty(WORKING_DIRECTORY));
                if (!rootDirectory.isPresent()) {
                    throw new MissingArgumentException("Server needs a working.directory env entry");
                }
                return this;
            }

            public Builder configurationPath(ConfigurationPath path) {
                configurationPath = Optional.of(path);
                return this;
            }

            public Builder configurationFromClasspath() {
                configurationPath = Optional.of(new ConfigurationPath(FileSystem.CLASSPATH_PROTOCOL));
                return this;
            }

            public Configuration.Basic build() {
                ConfigurationPath configurationPath = this.configurationPath.orElse(new ConfigurationPath(FileSystem.FILE_PROTOCOL_AND_CONF));
                JamesServerResourceLoader directories = new JamesServerResourceLoader(rootDirectory
                    .orElseThrow(() -> new MissingArgumentException("Server needs a working.directory env entry")));

                return new Basic(
                    configurationPath,
                    directories);
            }
        }

        public static Builder builder() {
            return new Builder();
        }

        private final ConfigurationPath configurationPath;
        private final JamesDirectoriesProvider directories;

        public Basic(ConfigurationPath configurationPath, JamesDirectoriesProvider directories) {
            this.configurationPath = configurationPath;
            this.directories = directories;
        }

        @Override
        public ConfigurationPath configurationPath() {
            return configurationPath;
        }

        @Override
        public JamesDirectoriesProvider directories() {
            return directories;
        }

        @Override
        public String toString() {
            return MoreObjects.toStringHelper(this)
                .add("configurationPath", configurationPath)
                .add("directories", directories)
                .toString();
        }
    }

    static Basic.Builder builder() {
        return new Basic.Builder();
    }

    ConfigurationPath configurationPath();

    JamesDirectoriesProvider directories();
}
